Typical, disc brake systems include a support bracket, two more brake pads, a caliper, and a rotor. The at least two brake pads are mounted and located adjacent to the support bracket so that the brake pads move axially towards and away from the rotor. The disc brake system may include a pad clip that attaches to the support bracket and to a portion of the one or more brake pads so that the brake pads are held in the support bracket. The disc brake system may include one or more springs that attach to the brake pads to assist in retracting the brake pads. The addition of one or more clips and/or one or more springs may require modifications to be made to the support bracket, brake pads, caliper body, or a combination thereof so that the spring and/or pad clip may be used. In addition these springs may not be used with existing braking systems because the spring does not fit without the modifications discussed above. Examples of springs and pad retraction devices are disclosed in U.S. Pat. Nos. 4,364,455; 4,491,204; 5,249,647; 5,511,638; 5,537,103; 6,378,665; 6,920,965; 7,308,974; 7,467,693; and 8,393,441; U.S. Patent Application Publication No. 2002/0189911 and WO2011/126125 and Japanese Patent No. 56021633U all of which are expressly incorporated herein by reference for all purposes.
One problem faced by these springs is that they work with “new” brake designs, or brakes modified specifically for each design. These springs may not easily be added to existing systems when the brakes are changed so that the benefits of the spreader spring can be seen with used vehicles. These springs may require special pad clips, brake pads, pressure plates, support brackets, caliper housings, or other additional features so that the spreader spring is held in place.
Yet another problem of know springs is that some of the springs are “over the rotor” designs (i.e. the spring is placed directly over the rotor) and are subject to interference with moving parts such as the rotor or the wheel. For example, the spreader spring may contact the rotor, the caliper housing, or both and move out of contact with the brake pads, become damaged, or become tangled within other parts causing damage to the other parts such as the rotor, brake pads, fluid lines, tires, or a combination thereof. The over the rotor designs may require additional clips and/or support structures so that the spring does not contact other parts of the braking system, thus, adding expense to the brake system and preventing the spreader spring from being added to existing systems easily. Some over the rotor designs may require the caliper housing to be redesigned so that there is enough space for the spring to fit under the caliper housing.
Another such problem faced by known disk brake systems is lateral run out (LRO) and disk thickness variation (DTV). Each rotor will exhibit some LRO as the rotor rotates, and each rotor will have some variation in disk thickness. As the rotor moves the rotor may contact the brake pads at a high spot on the disk due to DVT, the rotor may contact the brake pads due to LRO, or both. After repeated contact with the brake pads a thin spot may be created in the disk, and this thin spot may further increase the variation in thickness across the disk otherwise known as “DVT growth.” As a result of DVT growth the driver may perceive an increase in torque and pressure via pedal pulsation, steering wheel shake or “nibble,” vibration of the vehicle, or a combination thereof. Thus, there is a need for a device that can be incorporated into known braking systems, which minimizes and/or eliminates DVT growth so that noise, vibration, & harshness (NVH) are reduced and/or eliminated. Thus, there is a need for a spreader spring that is light, strong, resistant to failure, and can be added into existing braking system without any modifications to the braking system and/or the spreader spring, or using other additional parts. Further, there is a need for a spreader spring that can attach to existing brake components with modification and/or addition of attachment points, connections, or both. It would be attractive to have a spreader spring that forms a removable connection with sufficient holding capabilities with one or more components of the brake system so that the spreader spring does not fall out during normal operation but can be added to the system during a brake pad change.